The table of contents’s short option is actually also supported—I got
tired of typing the long form quite fast as I use that option often—so
Pandoc.toc() works as well.

Pandoc can also be used as a
transform stream. This makes it easy to pipe some read stream through
pandoc. For example, this documentation file, index.md can
be converted to HTML and
outputted to STDOUT as follows:

Observe that the Pandoc.css method is called twice;
Pandoc adds both stylesheets to the HEAD element of the generated HTML.
All pandoc’s command line options that can occur more than once, such as
--include-in-header or --variable, have the
same behavior: you can call these methods as often as you like.